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/*
*
* Copyright (c) International Business Machines Corp., 2009
* Copyright (c) 2014 Oracle and/or its affiliates. All Rights Reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
* the GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <unistd.h>
#include "test.h"
#include "tst_pid.h"
#include "old_safe_file_ops.h"
#include "tst_safe_macros.h"
#include "lapi/syscalls.h"
#define PID_MAX_PATH "/proc/sys/kernel/pid_max"
#define THREADS_MAX_PATH "/proc/sys/kernel/threads-max"
#define CGROUPS_V1_SLICE_FMT "/sys/fs/cgroup/pids/user.slice/user-%d.slice/pids.max"
#define CGROUPS_V2_SLICE_FMT "/sys/fs/cgroup/user.slice/user-%d.slice/pids.max"
/* Leave some available processes for the OS */
#define PIDS_RESERVE 50
pid_t tst_get_unused_pid_(void (*cleanup_fn) (void))
{
pid_t pid;
SAFE_FILE_SCANF(cleanup_fn, PID_MAX_PATH, "%d", &pid);
return pid;
}
/*
* Get the effective session UID - either one invoking current test via sudo
* or the real UID.
*/
static unsigned int get_session_uid(void)
{
const char *sudo_uid;
sudo_uid = getenv("SUDO_UID");
if (sudo_uid) {
unsigned int real_uid;
int ret;
ret = sscanf(sudo_uid, "%u", &real_uid);
if (ret == 1)
return real_uid;
}
return getuid();
}
static int read_session_pids_limit(const char *path_fmt, int uid,
void (*cleanup_fn) (void))
{
int max_pids, ret;
char max_pid_value[100];
char path[PATH_MAX];
ret = snprintf(path, sizeof(path), path_fmt, uid);
if (ret < 0 || (size_t)ret >= sizeof(path))
return -1;
if (access(path, R_OK) != 0) {
tst_resm(TINFO, "Cannot read session user limits from '%s'", path);
return -1;
}
SAFE_FILE_SCANF(cleanup_fn, path, "%s", max_pid_value);
if (!strcmp(max_pid_value, "max")) {
SAFE_FILE_SCANF(cleanup_fn, PID_MAX_PATH, "%d", &max_pids);
tst_resm(TINFO, "Found limit of processes %d (from %s=max)", max_pids, path);
} else {
max_pids = SAFE_STRTOL(max_pid_value, 0, INT_MAX);
tst_resm(TINFO, "Found limit of processes %d (from %s)", max_pids, path);
}
return max_pids;
}
static int get_session_pids_limit(void (*cleanup_fn) (void))
{
int max_pids, uid;
uid = get_session_uid();
max_pids = read_session_pids_limit(CGROUPS_V2_SLICE_FMT, uid, cleanup_fn);
if (max_pids < 0)
max_pids = read_session_pids_limit(CGROUPS_V1_SLICE_FMT, uid,
cleanup_fn);
if (max_pids < 0)
return -1;
return max_pids;
}
static int get_used_pids(void (*cleanup_fn) (void))
{
DIR *dir_proc;
struct dirent *ent;
char status_path[PATH_MAX];
int used_threads, used_pids = 0;
dir_proc = SAFE_OPENDIR("/proc");
while ((ent = SAFE_READDIR(dir_proc))) {
if (isdigit(ent->d_name[0])) {
snprintf(status_path, sizeof(status_path), "/proc/%s/status", ent->d_name);
if (!FILE_LINES_SCANF(cleanup_fn, status_path, "Threads: %d", &used_threads))
used_pids += used_threads;
}
}
SAFE_CLOSEDIR(dir_proc);
return used_pids;
}
int tst_get_free_pids_(void (*cleanup_fn) (void))
{
int max_pids, max_session_pids, max_threads, used_pids = get_used_pids(cleanup_fn);
SAFE_FILE_SCANF(cleanup_fn, PID_MAX_PATH, "%d", &max_pids);
SAFE_FILE_SCANF(cleanup_fn, THREADS_MAX_PATH, "%d", &max_threads);
max_pids = MIN(max_pids, max_threads);
max_session_pids = get_session_pids_limit(cleanup_fn);
if ((max_session_pids > 0) && (max_session_pids < max_pids))
max_pids = max_session_pids;
if (max_pids > PIDS_RESERVE)
max_pids -= PIDS_RESERVE;
else
max_pids = 0;
/* max_pids contains the maximum PID + 1,
* used_pids contains used PIDs + 1,
* so this additional '1' is eliminated by the substraction */
if (used_pids >= max_pids) {
tst_brkm(TBROK, cleanup_fn, "No free pids");
return 0;
}
return max_pids - used_pids;
}
pid_t tst_getpid(void)
{
return syscall(SYS_getpid);
}
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